JP2796858B2 - Two-signal simultaneous receiver - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a two-signal simultaneous receiving apparatus capable of simultaneously receiving two signals having different operating frequencies.

(Prior Art) When operating a wireless communication device, there are cases where two signals having different operating frequencies are simultaneously listened to on two reception paths, and one of the two signals is extracted as necessary. In particular, it has recently been demanded that two signals in the same frequency band such as the HF band can be simultaneously listened to and one of them can be extracted.

FIG. 2 is a block circuit diagram of an example of a conventional two-signal simultaneous receiving apparatus. In FIG. 2, an input signal received by an antenna 1 is appropriately selected and amplified by a high frequency amplifier 2 in a wide band. The output of the high-frequency amplifier 2 is branched into two, one of which is supplied to the first mixer 3 on the main side, and the other is supplied to the first mixer 4 on the sub side. The main-side first mixer 3 is supplied with a main-side first local oscillation signal from a main-side first local oscillator 5, and outputs a main-side first frequency-converted signal to a first intermediate frequency amplifier. 6 given. Further, the sub-side first mixer 4 is supplied with the sub-side first local oscillation signal from the sub-side first local oscillator 7, and outputs the sub-side first frequency-converted signal to the first intermediate frequency. It is provided to an amplifier 6. Further, the first intermediate frequency signal appropriately selected and amplified by the first intermediate frequency amplifier 6 is supplied to a second mixer 8 and mixed with a second local oscillation signal from a second local oscillator 9 to produce a second local oscillation signal. The frequency-converted signal is provided to the second intermediate frequency amplifier 10. The second intermediate frequency signal selectively amplified by the second intermediate frequency amplifier 10 is demodulated by the demodulator 11 by the local oscillation signal for demodulation from the local oscillator 12 for demodulation, and the low frequency signal is appropriately converted by the low frequency amplifier 13. And amplified from the speaker 14.

FIG. 3 is a block circuit diagram of another example of the conventional two-signal simultaneous receiving apparatus. In FIG. 3, an input signal received by an antenna 1 is appropriately selected in a wide band by a high frequency amplifier 2 and amplified and output. The output is branched into two, one of which is a first mixer on the main side. In 3, the signal is mixed with the first local oscillation signal on the main side from the first local oscillator 5 on the main side to perform a first frequency conversion on the main side. It is mixed with the first local oscillation signal on the secondary side from one local oscillator 7 to perform the first frequency conversion on the secondary side. Further, the first frequency-converted signal on the main side by the first mixer on the main side is supplied to the first intermediate frequency amplifier 15 on the main side.
The first intermediate frequency signal on the main side is appropriately selected and amplified, and supplied to the second mixer 16 on the main side. Then, in the second mixer 16 on the main side, the signal is mixed with the second local oscillation signal on the main side from the second local oscillator 17 on the main side, and the second frequency conversion on the main side is performed. It is provided to a second intermediate frequency amplifier 18. And further, the second intermediate frequency amplifier on the main side
The second intermediate frequency signal on the main side selectively amplified by 18 is demodulated by the demodulator 19 on the main side by the local oscillation signal for demodulation from the local oscillator 20 for demodulation on the main side, and the low frequency signal on the main side is low. The frequency is supplied to a frequency amplifier 13. Further, the sub-side first frequency-converted signal is supplied to the sub-side first intermediate frequency amplifier 21 by the sub-side first mixer 4, and the sub-side first intermediate frequency signal is appropriately selected and amplified. Then, it is supplied to the second mixer 22 on the secondary side.
Then, in the second mixer 22 on the sub side, the signal is mixed with the second local oscillation signal on the sub side from the second local oscillator 23 on the sub side, and the second frequency conversion on the sub side is performed. 2 to the intermediate frequency amplifier 24. Further, the sub-side second intermediate frequency signal selectively amplified by the sub-side second intermediate frequency amplifier 24 is converted by the sub-side demodulator 25 by the demodulation local oscillation signal from the sub-side demodulation local oscillator 26. The demodulated signal is supplied to the low-frequency amplifier 13 on the secondary side. This low frequency amplifier
By 13, the low-frequency signals on the main side and the sub-side are both amplified and amplified from the speaker 14.

The conventional two-signal simultaneous receiving apparatus shown in FIGS. 2 and 3 is excellent in that two signals to be simultaneously received on the main and sub receiving paths can be set independently of each other. . However, since the first mixer is provided separately on the main and sub-side receiving paths, the receiving sensitivity tends to be different between the main-side and sub-side receiving paths. This is because the receiving sensitivity is greatly affected by the circuit configuration from the antenna to the first mixer. In addition, the first mixer and the first local oscillator must be provided on the main and sub receiving paths, respectively, so that the circuit configuration is complicated, and various measures against unnecessary radiation are required. It becomes something.

FIG. 4 shows an example of a conventional two-signal simultaneous receiving apparatus having a simple circuit configuration and a low cost. FIG. 4 is a block circuit diagram of still another example of the conventional two-signal simultaneous receiving apparatus.

In FIG. 4, an input signal received by an antenna 1 is appropriately selected and amplified in a wide band by a high-frequency amplifier 2 and supplied to one first mixer 27. The first mixer 27 is supplied with a first local oscillation signal from a first local oscillator 28, and outputs a first frequency-converted signal. Further, the signal output from the first mixer 27 is 2
The signal is supplied to a main-side intermediate frequency amplifier 29 and a sub-side first intermediate frequency amplifier 21, respectively. The main-side intermediate frequency signal appropriately selected and amplified by the main-side intermediate frequency amplifier 29 is converted into a main-side demodulator local oscillator by the main-side demodulator 19.
Demodulated by the local oscillation signal for demodulation on the main side from 20,
The main-side low-frequency signal is supplied to the low-frequency amplifier 13.
The sub-side first intermediate frequency signal appropriately selected and amplified by the sub-side first intermediate frequency amplifier 21 is subjected to the second frequency conversion by the sub-side second mixer 22, and the sub-side second intermediate frequency 2 to the intermediate frequency amplifier 24. Further, the sub-side second intermediate frequency signal selectively amplified by the sub-side second intermediate frequency amplifier 24 is demodulated by the sub-side demodulator 25 and supplied to the low-frequency amplifier 13.

In the two-signal simultaneous receiving apparatus having the configuration shown in FIG. 4, the operating frequency of the main receiving path is set by adjusting the frequency of the first local oscillation signal of the first local oscillator 28. Then, by adjusting the frequency of the second local oscillation signal on the secondary side of the secondary local oscillator 23 on the secondary side, the operating frequency of the reception path on the secondary side is set.

(Problems to be Solved by the Invention) In the conventional two-signal simultaneous receiving apparatus shown in FIG. 4, the antenna 1 to the first mixer 27 are shared by the main and sub receiving paths. And the circuit configuration becomes simpler. Further, since the antenna 1 to the first mixer 27 are shared, the main-side intermediate frequency signal and the sub-side intermediate frequency signal output from the main-side intermediate frequency amplifier 29 and the sub-side first intermediate frequency amplifier 21, respectively. It is output at the same sensitivity level as the first intermediate frequency signal. However, a circuit for performing the second frequency conversion is further provided in the secondary-side receiving path, and the main-side and secondary-side receiving paths have different circuit configurations. The low-frequency signals demodulated in each of the reception paths are likely to be output at different sensitivity levels, and the reception sensitivity is likely to differ between the main-side and sub-side reception paths.

Further, when the first local oscillator 28 is adjusted to adjust the operating frequency of the main receiving path, there is a problem that the operating frequency of the sub receiving path also changes at the same time. Then, in order to keep the operating frequency of the receiving path on the secondary side as it is, the second local oscillator 23 on the secondary side must be adjusted again, and the operation is complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional two-signal simultaneous receiving apparatus, and does not cause a difference in receiving sensitivity between the main-side and sub-side receiving paths. It is an object of the present invention to provide a two-signal simultaneous receiving apparatus capable of independently setting the operating frequency of the receiving path on the secondary side for the adjustment of the operating frequency.

(Means for Solving the Problems) To achieve the above object, a two-signal simultaneous receiving apparatus of the present invention mixes an input signal with a first local oscillation signal from a first local oscillator by a first mixer. Do the first frequency conversion,
The first frequency-converted signal is split into two,
One of the signals is mixed with a second main local oscillation signal from a second local oscillator on the main side by a second mixer on the main side to form a second signal on the main side.
The other signal is mixed with the second local oscillation signal on the second side from the second local oscillator on the second side by the second mixer on the second side to perform second frequency conversion on the second side, By the control means, the frequency of the second local oscillation signal on the secondary side is made the same by the second local oscillator on the secondary side in conjunction with increasing and decreasing the frequency of the first local oscillation signal by the first local oscillator. It is configured to increase or decrease in the opposite direction by the amount of frequency change.

The first local oscillator and the secondary local oscillator are each formed by a frequency synthesizer, and the control means controls a frequency divider included in the frequency synthesizer as the first local oscillator by a first frequency divider. A frequency divider included in a frequency synthesizer serving as the second local oscillator on the secondary side is controlled by a sum of the frequency ratio set value and the shift value for operating frequency adjustment on the main side. Therefore, the control may be performed by a subtraction value of the operation frequency adjustment shift value on the main side.

Further, the frequency divider included in the frequency synthesizer as the secondary side local oscillator is configured to subtract the operating frequency adjustment shift value on the main side from the second frequency division ratio setting value and to reduce the frequency on the secondary side. It is also possible to adopt a configuration in which control is performed by a calculated value obtained by adding the operating frequency adjustment shift value.

(Function) The frequency of the first local oscillation signal is increased or decreased by the control means, and the frequency of the second local oscillation signal on the secondary side is increased or decreased in the opposite direction by the same amount of frequency change. Even if the frequency of the first intermediate frequency signal on the secondary side changes due to the adjustment of the operating frequency of the receiving path, the change is corrected by frequency conversion in the secondary mixer on the secondary side, and the operating frequency of the secondary receiving path is changed. Does not change. Therefore, the operating frequency of the secondary receiving path can be set independently of the operating frequency of the primary receiving path. In addition, since the antenna to the first mixer are shared, and the main and sub-side receiving paths have substantially the same circuit configuration, there is no difference in receiving sensitivity.

Then, the frequency divider of the frequency synthesizer as the first local oscillator is controlled by the sum of the first frequency division ratio setting value and the shift value for operating frequency adjustment on the main side, and the second local oscillator on the auxiliary side is controlled. If the frequency divider of the frequency synthesizer is controlled by a subtraction value of the shift value for operating frequency adjustment on the main side from the second frequency division ratio setting value, the frequency of the first local oscillation signal is changed by a simple configuration. The frequency of the second local oscillation signal on the side can be changed in conjunction with the reverse direction.

Further, the frequency divider of the frequency synthesizer as the secondary local oscillator is configured to subtract the main operating frequency adjustment shift value from the second division ratio setting value and to operate the secondary operating frequency adjustment shift value. , The operation frequency of the sub-side reception path can be adjusted and set independently and arbitrarily from the operation frequency of the main-side reception path by adjusting the sub-side operation frequency adjustment shift value.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG.
FIG. 1 is a block circuit diagram of an embodiment of a two-signal simultaneous receiving apparatus according to the present invention.

In FIG. 1, an input signal received by an antenna 1 is appropriately selected in a wide band by a high-frequency amplifier 2, amplified and provided to a first mixer 27. The first mixer 27 is supplied with a first local oscillation signal from a first local oscillator 30 formed by a frequency synthesizer, and outputs a first frequency-converted signal. Then, the signal output from the first mixer 27 is branched into two,
The intermediate frequency amplifier 31 and the first intermediate frequency amplifier 32 on the secondary side are respectively provided. And the first intermediate frequency amplifier on the main side
The first intermediate frequency signal on the main side is passed through 31 to the second mixer 33 on the main side.
, And is mixed with a main-side second local oscillation signal output from a main-side second local oscillator 34 formed by a frequency synthesizer to perform a main-side second frequency conversion.
The sub-side first intermediate frequency signal, which has been selectively amplified in a relatively wide range as appropriate by the sub-side first intermediate frequency amplifier 32, is provided to the sub-side second mixer 35, and is formed by a frequency synthesizer. The second local oscillation signal on the secondary side is output from the secondary local oscillator 36 on the secondary side and mixed with the secondary local oscillation signal on the secondary side to perform the secondary frequency conversion on the secondary side. And the second mixers 33, 35 on the main side and the sub side
Are supplied to a second intermediate frequency amplifier 37, and the second intermediate frequency signal output from the second intermediate frequency amplifier 37 is demodulated into a low frequency signal by a demodulator (not shown) at the subsequent stage. .

Here, the frequency synthesizer forming the local oscillator is formed by a PLL including a voltage-controlled oscillator 38, a low-pass filter 39, a frequency divider 40, and a phase detector 41, as is well known. Further, the phase detector 41 of these frequency synthesizer, the reference frequency signal f _s is given respectively. Then, the first local oscillator 30 and the second local oscillator 30
The division ratios of the frequency dividers 40 and 40 included in the frequency synthesizer as the local oscillator 36 are controlled by control means 42
Is variably controlled. The second local oscillator on the main side
The frequency division ratio of the frequency divider 40 included in the frequency synthesizer as 34 is given a second frequency division ratio set value S and is fixed.

The control means 42 includes a main counter 44 that counts the number of pulses output according to the rotation amount of the main dial 43, and a sub counter 46 that counts the number of pulses output according to the rotation amount of the sub dial 45. Have. Then, the main-side operating frequency adjustment shift value ΔM comprising the digital value output from the main counter 44 is provided to the main-side arithmetic unit 47 and the sub-side arithmetic unit 48. Further, a shift value ΔS for operating frequency adjustment on the sub-side composed of a digital value output from the sub-counter 46 is:
It is provided to the sub-operation unit 48. Here, if the main dial 43 and the sub dial 45 are rotated in the frequency increasing direction,
If the shift values ΔM and ΔS are positive values and the rotation is performed in the frequency decreasing direction, the shift values ΔM and ΔS are output as negative values. The first computing unit 47 is provided with a first division ratio setting value M, and the first operating frequency adjustment shift value ΔM is applied to the first division ratio setting value M. The frequency division ratio of the frequency divider 40 of the first local oscillator 30 is controlled by the sum (M + ΔM). The second computing unit 48 is provided with the second frequency division ratio set value S, and the second computing unit 48
Then, the main-side operating frequency adjustment shift value ΔM is subtracted from the second division ratio setting value S, and the sub-side operating frequency adjustment shift value ΔS is added, and the calculated value (S−ΔM +
ΔS) controls the frequency division ratio of the frequency divider 40 of the second local oscillator 36 on the secondary side.

In such a configuration, the first band is set by setting the reception band.
And the second division ratio setting values M and S are determined in advance. And
By rotating the main dial 43, the first local oscillator 30
The frequency division ratio of the frequency divider 40 is adjusted, and the operating frequency of the main receiving path is arbitrarily adjusted. At this time, since the operation value (S−ΔM + ΔS) output from the sub-operation unit 48 also changes in conjunction with this, the division ratio of the frequency divider 40 of the sub-second local oscillator 36 is also adjusted and controlled. The frequency of the second local oscillation signal on the secondary side changes, and the operating frequency of the reception path on the secondary side does not change. Further, by rotating the sub-dial 45, the division ratio of the frequency divider 40 of the sub-side second local oscillator 36 is adjusted and controlled, and the operating frequency of the sub-side reception path is independently and arbitrarily adjusted. Is done.

In the above embodiment, the frequency divider of the main-side second local oscillator 34 is provided with a constant second division ratio set value S, and the frequency of the main-side second local oscillation signal is Immutable,
The present invention is not limited to this, and the frequency of the second local oscillation signal on the main side may be adjusted by appropriately changing the frequency division ratio. Then, the switching of such reception band, the first and second division ratio set value M, or switch the S, or may be switched to the reference frequency signal f _S. The second local oscillator 34 on the main side is
It is obvious that the present invention is not limited to the one formed by the frequency synthesizer, but may be a local oscillator having a fixed oscillation frequency.

(Effects of the Invention) Since the two-signal simultaneous receiving apparatus of the present invention is configured as described above, it has the following special effects.

In the two-signal simultaneous receiving apparatus according to claim 1, the control means causes the frequency of the second local oscillation signal on the secondary side to change in the opposite direction by interlocking with the adjustment of the frequency of the first local oscillation signal. Therefore, the frequency of the second intermediate frequency signal output from the second mixer on the secondary side does not change, and even if the operating frequency of the receiving path on the main side is adjusted and changed, the operating frequency on the secondary receiving path is changed. Are kept at the same frequency. The system from the antenna to the first mixer is a single system shared by the main side and the sub-side, and the circuit configuration is simple. In addition, the main path and the sub-side reception path share the same mixer up to the first mixer, and the configuration of the main-side and sub-side reception paths is almost the same. There is no difference.

In the two-signal simultaneous receiving apparatus according to claim 2, a frequency synthesizer is used for the first local oscillator and the second local oscillator on the auxiliary side, and the shift value for operating frequency adjustment on the main side is set to the first local oscillator. A simple configuration can be obtained by adding the first division ratio setting value to the divider of the sub-side local oscillator and subtracting the second division ratio setting value from the second division oscillator setting value. Accordingly, the frequencies of the second local oscillation signals on the main and sub sides can be adjusted in the opposite direction by the same amount of frequency change.

Further, in the two-signal simultaneous receiving apparatus according to the third aspect, the sub-side operating frequency adjusting shift value is added to the second dividing ratio set value in the sub-side second local oscillator frequency divider. Therefore, the operating frequency of the secondary receiving path can be adjusted with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of an embodiment of a two-signal simultaneous receiving apparatus according to the present invention, FIG. 2 is a block circuit diagram of an example of a conventional two-signal simultaneous receiving apparatus, and FIG. FIG. 4 is a block circuit diagram of another example of the conventional two-signal simultaneous receiving apparatus, and FIG. 4 is a block circuit diagram of still another example of the conventional two-signal simultaneous receiving apparatus. 27: first mixer, 30: first local oscillator, 33: main second mixer, 34: main second oscillator, 35: secondary second mixer, 36: secondary second mixer 2 local oscillator, 40: frequency divider, 42: control means, 44: main counter, 46: sub-counter, 47: main-side computing unit, 48: sub-side computing unit, M: first division ratio setting Value, S: second division ratio setting value, ΔM: shift value for adjusting the operating frequency on the main side, ΔS: shift value for adjusting the operating frequency on the sub side.

Claims (3)

(57) [Claims] An input signal is mixed with a first local oscillation signal from a first local oscillator by a first mixer to perform a first frequency conversion, and the first frequency-converted signal is divided into two. The signal is branched, and one of the signals is mixed with a main-side second local oscillation signal from a main-side second local oscillator by a main-side second mixer to perform a main-side second frequency conversion. Is mixed with the sub second local oscillation signal from the sub second local oscillator by the sub second mixer to perform sub second frequency conversion. In conjunction with increasing or decreasing the frequency of the first local oscillation signal by the local oscillator, the frequency of the second local oscillation signal on the secondary side is changed by the same amount of frequency change in the opposite direction by the second local oscillator on the secondary side. A two-signal simultaneous receiving apparatus characterized by being configured to increase and decrease. 2. The two-signal simultaneous reception signal according to claim 1, wherein said first local oscillator and said second local oscillator are respectively formed by a frequency synthesizer, and said control means is configured as said first local oscillator. The frequency divider included in the frequency synthesizer is controlled by the sum of the first division ratio setting value and the shift value for operating frequency adjustment on the main side, and the frequency synthesizer as the second local oscillator on the sub side is controlled by the frequency synthesizer. A two-signal simultaneous receiving apparatus, wherein a frequency divider included is controlled by a subtraction value of a shift value for operating frequency adjustment on the main side from a second frequency division ratio set value. 3. The two-signal simultaneous receiving apparatus according to claim 2, wherein a frequency divider included in a frequency synthesizer serving as the second local oscillator on the secondary side is provided with a frequency divider based on the second frequency division ratio set value. A two-signal simultaneous receiving apparatus, wherein the two-signal simultaneous receiving apparatus is configured to subtract the operating frequency adjustment shift value on the side and control the calculated value by adding the operating frequency adjustment shift value on the secondary side.